Received: November 29, 2007.

Accepted: April 16, 2008.

Abstract published online: May 12, 2008.

Full paper published online: August 31, 2008.

PHARMACOLOGICAL CHARACTERIZATION OF VENOMS OBTAINED FROM MEXICAN TOXOGLOSSATE GASTROPODS ON ISOLATED GUINEA PIG ILEUM

ROJAS A (1), FEREGRINO A (1, 2), IBARRA-ALVARADO C (1), AGUILAR MB (2), FALCÓN A (2), HEIMER DE LA COTERA E (2)

(1) Laboratory of Chemical and Pharmacological Research on Natural Products, School of Chemistry, Autonomus University of Querétaro, Santiago de Querétaro, Querétaro State, Mexico; (2) Marine Neuropharmacology Laboratory, Department of Cellular and Molecular Neurobiology, Institute of Neurobiology, National Autonomous University of Mexico, Santiago de Querétaro, Querétaro State, Mexico.

ABSTRACT: The protein-containing extracts prepared from the venom ducts of Conus austini, Conus spurius andPolystira albida caused a concentration-dependent inhibition of spontaneous contractions in guinea pig ileum. The most potent extract was obtained from P. albida venom ducts (IC50 = 0.11 ± 0.02 µg protein/mL). The three extracts produced a moderate inhibition of contractions elicited by acetylcholine (ACh 1 µM), suggesting the presence of anticholinergic compounds. The contractile response elicited by nicotine (10 µM) was significantly reduced by the extracts prepared from the ducts ofC. austini andP. albida, which indicates that the venom produced by these species contains toxins that target neuronal nicotinic receptors. All three extracts significantly inhibited contractions evoked by histamine (0.5 µM), particularly those fromC. spurius andP. albida. These findings reveal the presence of antihistaminergic compounds not previously described in any conoidean venom. Finally, we found that only the extract prepared from C. spurius ducts decreased KCl (60 mM)-induced contractions, indicating that the venom of this snail contains compounds that block voltage-dependent Ca2+ or Na+ channels.

KEY WORDS: Conoidea, Conus austini, Conus spurius, guinea pig ileum, Polystira albida, Turridae.

CONFLICTS OF INTEREST: There is no conflict.

FINANCIAL SOURCE: Proyecto de Redes 2004 (PROMEP-SEP); CONACYT C01-47432 (A. Rojas), 43667-J (C. Ibarra-Alvarado), 41477-Q (E. Heimer de la Cotera) and 43754-Q (M. Aguilar); PAPIIT-UNAM (Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica, Universidad Nacional Autónoma de México) IN-206701 (M. Aguilar), INX-211904 (M. Aguilar) and IN-204403 (E. Heimer de la Cotera).

CORRESPONDENCE TO:

ALEJANDRA ROJAS MOLINA, Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Cerro de las Campanas, Col. Centro, C.P. 76010, Querétaro, Qro, México. Phone: + 52 442 1 92 12 67. Email: rojasa@uaq.mx.